A pulsating sensation of blood vessels (generally arteries) due to ejection of blood by a heart (or machine) is known as a pulse. The Pulse is an abrupt expansion of an artery resulting from a sudden ejection of blood and transmission of the blood throughout an arterial system. A left ventricle of the heart contracts and ejects blood into the aorta, which carries the blood bolus through branches of peripheral arteries to various organs and tissues. The arterial pulse perceived by a clinician is the pressure pulse in a large, accessible artery. Generally, a pulse can be examined at sites such as radial, carotid, subclavian, brachial, femoral popliteal, posterior tibial, dorsalis pedis etc., and in clinical practice, a common pulse examination site is a radial artery.
Pulse is related to various events of left ventricle, aorta, and peripheral arteries, and hence the pulse reflects a status of related organs. A common application of pulse'examination is a measurement of heart beats as each pulsation is a result of a ventricular systole. An absence of a pulse may suggest occlusion by a thrombus or dissection, and a diminished pulse may relate to vascular pathology or impairment of a cardiac function, for example. A low volume and amplitude (hypokinetic) pulse is found in low cardiac output while a high volume and amplitude (hyperkinetic) pulse is a sign of anxiety, exercise, fever hyperthyroidism, and anaemia, for example.
Pulse is also studied with other functions and events (e.g., inspiration and expiration related changes as pulsus paradoxus). Pulse changes according to various factors such as age, time; disease state (e.g., increases in fever), ongoing treatment, etc., and these aspects help physicians diagnose a patient. Thus, pulse examination may also be helpful in evaluation of drug response and patient monitoring.
There are various invasive and noninvasive methods to study blood flow through arteries. Invasive methods include insertion of a catheter to study blood flow in arteries. Noninvasive techniques include doppler ultrasonic probe, pressure sensors, and impedance plethysmography, (e.g., determining changing tissue volumes in the body based on a measurement of electric impedance at a body surface).
Pulse examination based research currently aims at cardiovascular health, identification of risk factors and early detection of diseases.